1. Field of the Invention
The present invention relates to a plasma display device, and more particularly, to a plasma display device having an improved structure by forming an electrode formed on a transparent front substrate using a conductive metal.
2. Description of the Related Art
A plasma display device forms a picture image by discharging a gas sealed between opposing substrates having a plurality of electrodes and exciting a phosphor by ultraviolet rays generated during the discharge.
The plasma display device is classified into a direct current (DC) plasma display device and an alternating current (AC) plasma display device depending on its discharge types. Also, the plasma display device is largely classified into an opposing discharge type and a surface discharge type depending on its electrode structure.
In the DC plasma display device, all electrodes are exposed to a discharge space, and charges move directly between the electrodes. In the AC plasma display device, at least one electrode is surrounded by a dielectric layer and a discharge occurs due to an electrical field of wall charges.
FIGS. 1 and 2 show an example of a conventional surface discharge type plasma display device.
Referring to the drawing, first electrodes 11 as an address electrode are formed in strips on a rear substrate 10. A dielectric layer 12 formed on the rear substrate 10 is coated on the first electrode 11. Partitions 13 for defining a discharge space and preventing electrical and optical crosstalk between neighboring discharge cells are formed on the dielectric layer 12 so as to be parallel to the first electrode 11.
A front substrate 16 is coupled above the partition 13. On the lower surface of the front substrate 16, second electrodes 14 as scanning electrodes and third electrodes 15 as common electrodes are alternately formed to be perpendicular to the first electrodes 11 The second and third electrodes 14 and 15 are formed of transparent materials, and bus electrodes 14a and 15a for reducing line resistance of the second and third electrodes 14 and 15 are respectively provided thereon.
Also, on the lower surface of the front substrate 16, a dielectric layer 17 and a protective layer 18 are sequentially formed so that the second and third electrodes 14 and 15 are buried therein. A fluorescent layer 19 is coated at at least one side of the discharge space defined by the partitions 13.
In the plasma display device thus constructed, since the second and third electrodes 14 and 15 are formed of transparent ITO, an ITO film forming and patterning processes are necessary. ITO, however the conductivity is rather poor so that the operating voltage level must be high. One conventional way to solve the problem of poor conductivity is to form bus electrodes 14a and 15a on top of the second and third electrodes made of transparent ITO. Forming a bus electrode makes the PDP manufacturing process more complicated, thus increasing the cost. As an alternative, U.S. Pat. No. 5,640,078 (Amemiya) discloses ITO-electrodes having protrusions at every emitting pixel in order to decrease the amount of current flowing in the electrodes. However, prior art PDPs using ITO-based electrodes have not been able to fully overcome their inherent poor conductivity problem, and as a result, there is a problem in that power consumption is high, which is a major drawback in PDPs, in addition to the problem of high costs for the ITO material.
To solve the above problems, it is an object of the present invention to provide a plasma display device with an improved structure, capable of obviating the need for transparent electrodes.
Accordingly, to achieve the above object, there is provided a plasma display device including front and rear substrate disposed parallel to and facing each other, first electrodes formed in strips on the rear substrate, second and third electrodes formed of a conductive metal in strips on the lower surface of the front substrate so as to be perpendicular to the first electrodes, and at least one auxiliary electrode formed adjacent to the second and third electrodes.
Here, the auxiliary electrode is formed of a conductive metal.
According to another aspect of the present invention, there is provided a plasma display device including front and rear substrate disposed parallel to and facing each other, first electrodes formed in strips on the rear substrate, second and third electrodes formed of a conductive metal in strips on the lower surface of the front substrate so as to be perpendicular to the first electrodes, and auxiliary electrode portions extending from at least one of the second and third electrodes and formed therebetween.